The lift balls on all my Cat 1 tractors are 1-3/8" wide. It seems to be a standard.
Between you, Jim, and me we have experienced 1 good and 2 bad off that assembly line. They appear to be experiencing some variability - - or maybe there are two different production runs and they have become mixed. I am sending mine back. HF has sent me a postage paid label. They will send me another after receiving the return. I just called HF cust serv 800-4443353 and spoke to Brandon Cook in Tech Support. He said the return rate on this item is low, so maybe there arent too many bad ones out there. Or else many people are just modifying them to fit. or, shudder, grinding their tractor balls.
Does either of yous hitches have a problem with being able to set the top hook in the 2 lowest adjustment positions? mine has interference with the top bar here in addition to the subject problem with lift arm fit.
Item of probable interest: I found that Brandon can order that top hitch adapter shown in the quick hitch instructions. The price is $11.71 PP with a 6-8 WK lead. Nice to have at the price.
Larry